摘要
土壤有机碳（SOC）具有空间变异性，其变异程度依赖于空间尺度，多尺度研究SOC变异性特征及其对空间尺度拓展的响应对精确估算土壤碳储量具有重要意义。本研究以黄淮海农业区为研究区域，利用全国第二次土壤普查资料记录的1875个土壤剖面，设定4级行政区尺度，即大区、省级、市级和县级，研究了不同土壤深度（0～20、20～30、30～50、50～70和70～100cm）有机碳含量的变异性特征及其对行政区尺度拓展的响应。研究结果表明：黄淮海农业区SOC含量变异系数均值随着行政区尺度的增大和土壤深度的增加而增大，范围为县级尺度0～20cm表层的33．68％到大区尺度70～100cm底层的81．02％；两行政区尺度间的跨度越大，其变异度越大，尺度间变异度呈明显的阶梯状，表现为3个尺度等级（大区一县级）〉2个尺度等级（省级一县级和大区一市级）〉1个尺度等级（省级一市级，市级一县级和大区一省级）；SOC含量变异系数均值与行政区面积为显著对数关系Y=a＋b×In（x），随着土壤深度的增加，SOC变异性对尺度的响应也越快。实际采样过程中，研究区域越大，采样深度越深，所需要的采样点数目越多。
Spatial variability of soil organic carbon （SOC） is scale dependent. Estimating spatial variability of SOC at different scales is of great significance for accurately predicting the SOC pool. Four administrative scales were made in this study, namely region, province, city and county. Variability of SOC content and its response to expansion of scale in different soil depth intervals （0 - 20, 20 - 30, 30 - 50, 50 - 70 and 70 - 100 cm） in the upland of the Huang-Huai-Hai agriculture region were examined based on coefficient of variation （CV） values using 1 875 profiles data obtained from the 2nd national soil survey of China. The results showed that the mean variability coefficient of SOC density increased with the expansion of scale and the increase of soil depth. The mean CV of SOC ranged from 33.68% at the county extent and 0 - 20 cm soil depth interval to 81.02% at the region extent and 70 - 100 cm soil depth. The CV ratio increased gradient with the rank between two scales increasing, that is three scale rank （region-county） 〉 two scale rank （province-county and region-city） 〉 one scale rank （province-city, city-county and region-province）. The mean CV of SOC had a significant logarithmic relationship with administrative area, namely y = a ＋ b× In （x）. The response of SOC variability to expansion of scale became quickly when soil depth increased. More soil sampling points are need if the study area is larger or sampling depth is deeper.
出处
《土壤》
CAS
CSCD
北大核心
2013年第4期648-654,共7页
Soils
基金
国家自然科学基金项目(No.40921061)
中国科学院战略性先导科技专项(XDA05050509)
国家重点基础研究发展计划(973计划)项目(No.2010CB950702)资助
